In HVAC (heating, ventilating and air conditioning) systems, air flow typically is formed by main lines or ducts leading to duct branches and further sub-branches for delivery of conditioned air throughout a structure. The ductwork in such a system typically steps down in size, and thus branch ducts are smaller in size than feeder or main ducts. In addition, it may be desired to divert air flow from a duct having a generally planer slide (such as a duct having a square or rectangular cross section) to a duct having a circular cross section.
One connector developed for such connection is referred to as a high efficiency takeoff (H.E.T.O., alternatively HETO). Such a connector is designed with a rectangular inlet opening and a flange assembly extending about that opening. A connector body extends from the rectangular inlet opening and assumes a cylindrical shape some distance from the rectangular opening, thereby defining a circular outlet. The circular outlet is offset downstream relative to the rectangular opening. Previously, such a high efficiency takeoff connector has been formed from multiple sheets of metal. For example, two connector halves may be connected by rivets or welding together along a seam along a leading side of the body and a seam along a trailing side of the body. Additional metal parts may be added to fully define the flange assembly about the inlet opening.
Any time a seam is introduced into an HVAC duct work system, there exists the possibility for leakage of conditioned air from the system through that seam. In addition, fabricating a connector from two or more components introduces increased inefficiencies in manufacturing, both in requiring additional die forming capability and also in requiring additional labor through formation and assembly requirements.